The Access Grid Collaboration Environment
The Access Grid, a series of "designed spaces" that support group-to-group
collaboration for remote visualization or interactive applications, utilizes
a high-bandwidth environment for virtual meetings and events.
Creating a working collaboration requires having a way to establish and maintain
communication with one's collaborators. When your partners are in your own workplace,
whether an academic or a corporate environment, communication is a relatively
easy matter of holding meetings and engaging in casual social activities.
When your collaboration partners are not on-site, however, establishing and
maintaining communication are more difficult. At the Futures Lab at Argonne
National Laboratory (www.mcs.anl.gov/fl),
we often work with groups outside our local community, and we have developed
a theory about the stages of collaboration that proceeds along this continuum:
Awareness -> Interaction -> Cooperation -> Collaboration -> Virtual Organization
Awareness. Through journals, meetings, and word of mouth, we first become aware
of others in our field who share common interests or ideas.
Interaction. We interact with some of those colleagues at conferences and
meetings.
Cooperation and Collaboration. With a subset of those colleagues, we begin
to cooperate on projects or papers, and soon we have groups of people from different
organizations submitting joint proposals and finally entering into full collaborations.
Virtual Organization. As these groups grow and evolve, they eventually become
a virtual organization of work partners.
To maintain and support this virtual organization and still remain cost-effective,
we need a persistent virtual space where we can meet to share work and social
activities. Persistence is the property that allows us to visit the space at
any time, to hang out with others whenever we wish. The need for just such a
virtual space led us to create the Access Grid group-to-group collaboration
environment.
The Access Grid
The Futures Laboratory in the Mathematics and Computer Science Division at
Argonne National Laboratory is a small group (8 to 12 people) working in the
areas of advanced visualization, collaboration, and display technologies. Our
research partners are almost exclusively from universities or other national
laboratories. Based on the model of our own scientific collaborations, our space
supports small groups in collaborative efforts. The target space for the Access
Grid involves 3 to 10 people interacting on a regular basis with 3 to 5 similar
groups. Desktop tools are wholly inadequate for creating a persistent space
for this target audience; instead, a small or moderate-sized dedicated room
that can be set up for audio, video, and computer-based interactions is ideal.
Researchers at Argonne National Laboratory using the Access Grid. |
The goal of the Access Grid project is to enable high-quality group-to-group
interactions by providing a user experience that is a substantial improvement
over traditional desktop collaborative tools. We want to create a sense of presence
with others and allow for natural interaction modalities. These goals are accomplished
through multiple video streams emanating from a single space that provide varying
perspectives and that support hands-free, full-duplex audio interactions.
Shared visualization on the Access Grid: The Visible Human. |
The physical components that have evolved into standard specifications are
a dedicated room with a large-scale three-projector display wall and four computers
providing video capture, audio capture, display management, and control. Hands-free
full-duplex audio communication among all participating sites is accomplished
by strategic placement of high-quality microphones throughout the space and
by the use of professional-quality echo cancellation equipment. Scalability
of the environment comes from the use of IP multicast for all video and audio
streams. Full specifications and software downloads are available at www.accessgrid.org.
The Access Grid space at Argonne National Laboratory. |
We have also developed a standard suite of software to support this environment,
control the four computers and echo-cancel gear, and maintain certain applications
that are shared via the Access Grid. This software, called the Virtual Venue,
implements a room-based spatial metaphor that provides persistence, controls
the scope of interaction, and enhances navigation and discovery within the Access
Grid.
Applications
While collaboration is largely about communication, we often think of it in
terms only of the spoken and written word. In an electronic world there can
be many other means of exploring ideas—computer-generated visualizations, computer-aided
searching, shared software, image processing, virtual reality experiences, telepresence
experiments, or remote instrument operation. Enabling these communications is
an important part of the Access Grid research agenda. We have developed a small
set of tools and are working on others. For high-fidelity presentations, we
have created a distributed PowerPoint. In an Access Grid meeting, all remote
sites receive a copy of the slides and run a local copy of PowerPoint. A master
at the host site controls all remote PowerPoints, ensuring a high-fidelity version
of the presentation with very low latency slide changes. For more general presentation
needs, we use the Virtual Network Computer (VNC) software, which has a facsimile
of a screen with optional control. This is a lower-fidelity facsimile with a
higher transmission time, but it requires less advance setup and works for most
applications and across various operating systems.
Bringing visualization applications with high-performance rendering requirements
to the Access Grid presents more of a challenge. Most of our visualizations
are driven by the Visualization Toolkit (VTK) software and are rendered on high-performance
SGI computers or computational clusters. Access Grid computers do not possess
high-performance rendering engines and are already heavily loaded.
We have provided
a solution by developing a VTK video renderer and a headless video encoder for
placing visualization output on the Net as a video stream. We have patched the
VIC video client used by the Access Grid to send mouse and keyboard events back
to the VTK visualization application. This simple method of decoupling the control
from the rendering via a video stream has allowed us to trivially create visualization
applications that can be controlled by anyone. Distributed groups thus can jointly
explore visualizations by using natural interactions and directly interacting
with the images. This VTK/VIC software is available from the Futures Laboratory.
Others have also developed applications for delivering visualization experiences
to the Access Grid. The Electronic Visualization Laboratory at the University
of Illinois at Chicago, inventors of the CAVE, have streamed second versions
of CAVE applications with their CavernSoft middleware and are currently developing
an Access Grid supplementary system, AGAVE, for delivering 3D content to the
Access Grid. More information is available from the EVL Web pages (www.evl.uic.edu/).
At the University of New Mexico, the Flatland virtual reality environment has
been adapted to run on the Access Grid. (See www.ahpcc.unm.edu/NewsPress/ flatland_ag.html
for more information.)
Snapshot of time varying fractal deformation
of spherical geometry in the VTK software.
(Courtesy of Tony Lavoie.) |
Partnerships
The Access Grid was first conceived to facilitate collaboration between the
Futures Lab and university and D'E partners. We have had AG-enabled visualization
and computing partnerships with the University of Chicago, the University of
Utah, Lawrence Berkeley Laboratory, The University of Illinois at Chicago, the
University of Illinois at Urbana, Los Alamos National Laboratory, and Princeton
University. Existing collaborations with many universities have been strengthened
by the use of Access Grid nodes. The University of Kansas Chemical Engineering
Program is working with the University of Illinois; the Arctic Region Supercomputer
Center works with universities in Bozeman and Missoula, Montana; and the University
of New Mexico uses AG technology to collaborate with the Maui High Performance
Computing Center, which the school administers. Access Grid collaborations are
also being planned between the University of Chicago and Brown University medical
schools. The Access Grid has grown to the point (more than 25 active nodes,
over 40 in progress or planned) that many other collaborations of which we have
little knowledge are being enabled across the country. We have been quite pleased
with the system's ability to enable effective group-to-group collaborations.
Experiments
Experiments with the Access Grid technology outside the original target of
small group-to-group collaborations have been proposed and conducted by university
partners.
The first Access Grid sites—the University of New Mexico Albuquerque
High Performance Computing Center, the Maui High Performance Computing Center,
Boston University, the University of Utah, the University of Kentucky, Argonne
National Laboratory, and the NCSA Alliance sites at Access DC and at the University
of Illinois at Urbana—worked together in 1999 hardening the systems and networking
through a series of multiple-day, multi-site education and outreach meetings
called Chautauquas, sponsored by the NCSA Alliance. Three Chautauquas were hosted
by UNM, UKY, and BU. In 2000, Chautauquas were held at the Ohio Supercomputer
Center and at the University of Kansas, with participants from the original
six sites plus several others, including the Electronic Visualization Laboratory
at the University of Illinois at Chicago. Experiments are under way to deploy
this technology in support of remote education at tribal colleges in New Mexico.
The Globus group at ANL has performed distance education experiments by conducting
a two-day distributed tutorial among six Access Grid sites. A PETSc tutorial
was conducted via the Access Grid by the Ohio Supercomputing Center. In each
instance, the response from participants was good.
Shared visualization of a Raleigh-Taylor dataset. |
Participation in the Access Grid
The Access Grid specification and software are open source and are freely available
at the Access Grid Web site, where universities and their partners who wish
to build an Access Grid node will find all the information they need. Users
can join the Access Grid community by subscribing to the Ag-tech mailing list
([email protected]) where Access
Grid technical issues are discussed.
In January 2001, Argonne National Laboratory hosted a four-day Access Grid
retreat for academic and corporate institutions interested in joining the Access
Grid community and furthering the development of the Access Grid. More than
130 persons from almost 60 institutions were represented, a full-day tutorial
was held, and over 30 papers were presented. Proceedings are available at www.accessgrid.org.
Future projects include a large-scale experiment to broaden the visibility of
the annual SC convention by providing Access Grid-like capabilities in the technical
venues and inviting similarly equipped international sites to participate in
the conference from abroad. Many U.S. AG sites will also participate from their
respective locations. More information is available at http://www.scglobal.org.
An Open-Source Project
The Access Grid group-to-group collaboration environment provides a comfortable,
effective environment for face-to-face meetings of distributed collaborators.
Developed by members of the Futures Laboratory at Argonne National Laboratory,
Access Grid nodes have been deployed by the NCSA Alliance among our collaborators
and receive almost daily use. Visualization applications that have been integrated
into the AG framework allow concurrent multi-site collaborative visualization
sessions.
Access Grid technology has attracted the attention of users who have experimented
with distributed lectures, panels, tutorials, and multi-site, multi-day education
and outreach conferences, and who are planning performance event experiments
and distributed classrooms. Human factors studies are being proposed to learn
how the technology can be improved for its present use or modified for some
of the proposed new uses. The Access Grid is an open-source project, and new
users and contributors are welcome and encouraged.